This invention relates to a controller for video surveillance cameras and, in particular, to a controller which controls pan, tilt, zoom, focus and iris functions of video surveillance cameras in a closed-circuit television ("CCTV") security system.
The use of video cameras to monitor a location or premises has greatly increased over the years as a means for providing additional security and surveillance for the specified location. To increase the usefulness of video surveillance cameras, controllers have been designed to allow the user to operate and maneuver the cameras and their functions from a remote location. For example, various controllers have been designed to remotely operate and control the pan, tilt, zoom, focus and iris settings of video cameras and their lens assemblies. This allows the range and coverage realized by the cameras to be easily changed so as to adapt the cameras to various surveillance situations.
U.S. Pat. No. 4,945,367 to Blackshear ("Blackshear") discloses one example of a surveillance camera system with a camera and a computerized control system mounted in a spherical housing. The control system is controlled from a remote location by a hand-held joystick which controls panning and tilting of the camera with variable speed control as well as the operation of the camera's zoom, focus and iris settings. Panning of the camera occurs when the joystick is deflected side-to-side, while tilting occurs when the joystick is pushed forward or pulled backward.
The zooming function of the lens assembly with a fixed speed control is operated by a rotary movement of a knob located on the upper position of the joystick. Twisting of the knob on the joystick clockwise allows the lens to zoom-in, while twisting of the knob counter-clockwise allows the lens to zoom-out. The focus and iris functions of the lens assembly are manually controlled by switches mounted on the controller and cannot be operated simultaneously when panning or tilting.
While the above-described controller of the '367 patent enables adequate remote operation and control of a video surveillance camera, the controller has certain drawbacks. One drawback is that it requires two-handed operation for simultaneously controlling the panning and tilting and the lens functions, i.e., zoom, focus or the like of the camera. This restricts the user to controlling only one camera at a time, since both hands of the user must be used. Further, this two-handed operation requires the user to look away from the video monitor to locate a particular function key on the controller, thereby interrupting the tracking of the subject.
Other controllers which have been developed have other limitations. Thus, many of these controllers have a fixed speed for controlling panning and tilting of the camera being controlled. Therefore, if the user attempts to track a person, the pan and tilt speeds of the controller cannot be adjusted in accordance with the movement of the person. In addition, if the user tries to zoom-in on a specific scene, the pan and tilt speeds move the camera too quickly resulting in "overshooting" the desired view. This speed control problem also occurs in the speed control of the lens functions of the camera, resulting in a particular lens function operating too rapidly or too slowly.
In addition, the program code of the current controllers which determines the operating characteristics and functionality of the camera is difficult to up-grade and maintain. Typically, the program code is stored in a Read-Only-Memory ("ROM") or in an Electrically Erasable Programmable Read-Only-Memory ("EEPROM"). If there is a programming error or a new feature needs to be added and the program code must be changed in the controller, the ROM/EEPROM of the controller must then be physically replaced with a new ROM/EEPROM containing the new program code.
It is therefore an object of the present invention to provide a controller which allows for single-handed control of the pan, tilt, zoom, focus and iris settings or functions of a video surveillance camera in a CCTV security system.
It is a further object of the present invention to provide a controller which allows for easy speed control of a video surveillance camera.
It is an additional object of the present invention to provide a controller with easy access key functions and locations to facilitate use of the controller by the user.
It is a further object of the present invention to provide a controller which allows for easily loading of a program code into the memory as well as the ability to designate the particular functions of the buttons based upon the user's preference.
It is an additional object of the present invention to provide a controller with a design and structure which permits ready and comfortable use.